Sclerobregma nanhaiensis sp. nov. holotype (TIO-Poly-149) A entire specimen in dorsal view B anterior end in dorsal view (right parapodium of chaetiger 2 dissected) C anterior end in ventro-lateral view D middle segments in lateral view E chaetiger 2 in anterior view F chaetiger 28 in anterior view G notopodium of chaetiger 2 in anterior view H neuropodium of chaetiger 2 in anterior view I lyrate chaetae. Abbreviations: aS, acicular spine; br, branchiae; cc, capillary chaetae; ch, chaetiger; dC, dorsal cirrus; fH, frontal horn; mo, mouth; neP, neuropodium; noP, notopodium; per, peristomium; pr, prostomium; sc, spinous chaetae; vC, ventral cirrus; vG, ventral groove. Scale bars: 1 mm (A); 500 μm (B–D); 200 μm (E); 100 μm (F–H); 20 μm (I).